Resinous coating composition



form drying of such enamelson storage.

thermore, there are marked limitations on the amount of metallic drierwhich can be used Patented June 30,1942

uNiTEo STATES-PATENT OFFICE BESINOUS COATING COMPQSITION Daniel MaceGowing,= Upper Darby, and Philip Francis Sanders, Philadelphia, Pa.,assignors to E. I. du Pont de Nemours & Company, Wil- I mington, DeL, acorporation of Delawarev No Drawing. Application April 18, 1940,

. Serial No. 330,268

- 9 Claims. (01. zoo-a2) This invention relates to decorative andprotective coating compositions and more particularly to such coatingcompositions having a resinous vehicle as a base.

In the manufacture of so-called air drying alkyd resin enamels it is acommon practice to use drying oil or semi-drying oil or oil acidmodified polyhydric alcohol-polycarboxylic acid resins as the sole orprincipal resin vehicle. These resins as commonly prepared areconsidered as high acid number resins, the acid number averaging between30 and'40 but often being considerably above 40. Enamels prepared fromsuch I resins often do not exhibit a uniform retention of dryingproperties on storage and may thus become unreliable so far as theresults desired insofar as defined by the appended claims. The 7 partsare by weight.

in the practical application thereof is concerned.-.

For example, a black air drying enamel which when freshly prepared driessatisfactorily in five I hours may not dry satisfactorily in ten hoursafter container storage under normal conditions. I i

This loss of drying ability of the enamels is not uniform and furthernot absolutely reproduce ible which factors add to the complexity of thesituation. The use of an extra quantity of metallic drier in the enamelas initially prepared is ineifective in assuring a maintenance of uni-Furwithout jeopardizing other desirable and neces-' sary properties ofthe enamels.

This invention has as a principal object the provision of means forpreparing synthetic resin enamels having satisfactory initial airdryingproperties and retaining these properties on storage. A furtherobject is the provision of means for preparing such enamels in whichdrying oil, semi-drying oil or oil acid modified poly-- hydricalcohol-polybasic acid resins make up the principal vehicle. A stillfurther object is the manufacture of such enamels possessing theretention of; satisfactory drying properties while maintaining the;other necessaryand desirable properties of the enamel as build, glossetc.

' Other objects will be apparent asthe descrip-, tion of the inventionproceeds,

These objects are accomplished in the present invention by incorporatinginto the enamel composition a small percentage of diphenyl .or.triphenyl guanidine. I I I The invention will be more fully understoodfrom the following examples which are given by way of'illustration butnot by limitation except Alkydnresing-Apis a 52% linseed oil modifiedglycerol phthalate having an acid number of approximately 6.5.

Alkyd resin is is a Chinawood-linseed oil modified glycerol phthalatehaving an acid num ber of approximately 35.

The drier solutions are solutions of the naphthenates of the respectivemetals in mineral spirits; the solutions containing 2%, 3%, and

16% respectively, of cobalt, manganese, and lead.

The enamel is prepared in any manner well known in the art. The pigmentis dispersed in a part or the whole of thealkyd resin solution or towhich has been added a portion of the petroleum naphtha by, any suitableor available conventional means as a roller mill, ball or pebble mill,etc. The 'drier solutions are then added and the mass thoroughlyagitated. Finally the diphenyl guanidine is added and, if not allpreviously added, the remainder of the petroleum naphtha. The enamel isnow ready for use.

The diphenyl guanidine may be added to the final enamel or to thedispersion of the pigment in the high acid number resin. The point atwhich the diphenyl guanidine is added is not critical.

This'enamel when flowed or sprayed on a suitable base as ,a steel panel,air dried tack free in approximately 3 hours. An enamel of the samecomposition as to ingredients and amounts but containing no diphenylguanidine requires approximately 4% hours to air dry tack free.

This black enamel after being stored in a suitably closed container forsix months dried tack free in. approximately 3 hours, whereas the sameenamel containing no diphenyl guanidine required 9 hours to air dry tackfree. It is thus apparent that the enamelcontaining the diphenylguanidine not only air dries initially more quickly than a similarenamel containing no diphenyl guanidine but also retains its desirabledrying properties on storage.

EXAMPLE 11 White enamel r Parts Antimony oxiden 12.17 Titanium dioxide.l2.17 Alkyd resin A -9 4.50 Alkyd resin B 21.40 Cobalt driersolution..- .82 Manganese drier solution .20 Lead drier solution .84.Diphenyl guanidine --L .78 Petroleum naphtha 47.12

The alkyd resins and the drier solutions used w in the above enamel werethe same as used in the previous example. The enamel was preparedaccording to the procedure described under Ex ample I. K.

This enamel when applied to a suitably prepared base air dries inapproximately 3 hours,

whereas a similar enamel containing no diphenyl guanidine requiresupwards of hours 4 to air dry tack tree.

on storage for a period of 5 months the enamel containing the diphenylguanidine required four hours to air dry tack free while the enamelcontaining no diphenyl guanidine required 8 hours to air dry tack free,thus increasing its drying time by approximately 60%.

In the preceding examples the amount of diphenyl guanidine based on theresin content of the enamels is approximately 3%.

Alkyd resin A is the same as used in Examples I and II. Alkyd C is a 45%Chinawood-linseed oil modified glycerol phthalate having an acid numberof approximately 45. The drier solutions used were as described underExample I.

This enamel was prepared according .to the procedure previouslydescribed and contained approximately 1% of diphenyl guanidine based onthe resin content.

This enamel was found to air dry tack freein approximately,4 hours. Asimilar composition containing no diphenyl guanidine required 5 hours toair dry tack free, the diphenyl guanitack free in approximately 2 hoursas compared to the 5 hours required for the same enamel containing nodiphenyl guanidine. When the amount oi. diphenyl guanidine was increasedbeyond 10% no improvement in the drying time oi! the enamel resulted;there resulted in fact a reduction in the drying time improvement of theenamel. Compositions containing less than 1% of diphenyl guanidine basedon the resin content show a perceptible improvement in reduction ofdrying time even when as low as 0.10% was used. Amounts less than 0.10%showed no improvement. a The effective range for diphenyl guanidinecontent of the enamel based on the resin content is 0.10 to 10%, with apreferred range 01' 3-5%.

In the claims the term diphenyl guanidine is intended to be inclusive oftriphenyl guanidine since these two compounds are full equivalents inthe present invention and are interchangeable.

All these compositions with the varying amounts of diphenyl guanidineretained their drying properties 'on storage in contrast to a markedincrease in time required to dry satisfactorily after storage of similarenamels containing no diphenyl guanidine. While the above examples areconfined. to black and white enamels the invention is applicable toother coloredenamels in whichvarious types of pigments and fillers maybe used as well as to unpigmented compositions.

The diphenyl guanidine in the enamels does not serve simply as anadditional drier since it has been found to be ineflective incompositions containing no drier, in some instances having a detrimentaleflect. Furthermore; its eflective ness vvithrespect to drieris-selective, e. g. be-. ing effective with cobalt drier when usedalone, slightly effective when used with manganese drier alone, butineffective when used alone with lead drier. However, it issatisfactorily effective when used with a combination or any two of themetallic driers or with a combination of the three as noted in theexamples. This selective action 'is or a qualitative rather than or aquantitative I nature. I The diphenyl guanidine is further ineflectivewith'low acid number fatty oil or oil acid modified polyhydricalcohol-polycarboxylic acid resins. While the acid number of fattyoil.or oil.

- acid modified alkyds commonly used in the preparation oi' enamelsmaybe as high as 65 or above,

the average 01' those mostly used is between 20 I and 40. The minimumacid number of the resin for the diphenyl guanidine to be eflective hasbeen found to be approximately 10. The range then i'or acid number ofthe alkyd resin may, conveniently be from 10 upwards No maximum acidnumber for the alkyd resin (as ordinarily used) in which the diphenylguanidine was ineffective has been found. a The drying oil, semi-dryingoil, or oil acidmod- I ified alkyd resins used in the present inventiondine containing enamel therefore showing a decrease in initial-dryingtime 01' 25%.

An enamel similar to the above containing 5% diphenyl guanidine based onthe resin content was found to air dry tack-free in approximately 2%hours or 50% 01' the time required for the dry tack free.

Another enamel containing 10% of diphenyl I guanidine based on the resincontent air dried enamel containing no diphenyl guanidine to air areusually such as are modified to the extent of from 35to65%.

While the above examples arein connection with air drying enamels theinvention is also applicable for use in the preparation oi bakingenamels.

It might appear that the diphenyl-guanidine would be effective with anyso called high acid number vehicle. This has not, however, been found tobe the case, since the diphenylguanidine is ineflective as in thepresent instance with oleoresinous, type vehicles of comparable acidnumb er.

The compositions of the present invention are adaptable for use asdecorative and protective coating compositions for application tovarious surfaces as wood, metal, glass, molded synthetic resin articles,hard rubber, etc. The compositions may be applied by brushing,spraying,.dip-

ping, roller coating processes, etc., orby any other means known tothose skilled in the art.

The compositions are particularly adaptable to the refinishing ofautomotive vehicle bodies by .the usual standard procedures.

It will be apparent from he above that enamel compositions have beenprepared which substantially retain their initial drying properties on.

storage and in addition possess improved initial drying properties, withrespect to time, over alkyd resin enamels used in the present state ofthe art. Furthermore, these improved properties are imparted to theenamels without any sacrifice of other desirable and'necessary.properties of the compositions as build, gloss, color,

'etc. Other advantages will be apparent to those skilled in the art ofpreparing such compositions. It is apparent that many widely differentembodiments of this invention may be made without departing from thespirit and scope thereof,

and therefore, it is not intended to be limited exlead soaps, and from.iO tol% of material selected from the class consisting of diphenylguanidine and triphenyl guanidine'based on the resin content of theenamel.

2. An enamel comprising an oil modified alkyd resin having an acidnumbergreater than 10, from 3 to 5% thereof of material selected from theclass consisting of diphenyl guanidine and triphenyl guanidine, and atleast two driers selected from the class consisting of cobalt,manganese, and lead soaps.

3. The product of claim 2 in which the oil is a drying oil.- f

4. The product of claim 2 in which the resin modified with a semi-dryingoil. s

5. The product of claim 2 in which the resin is modified with oil acids.

6. The product of claim. 2 in which the resin 1 is modified to theextent of from to lected from the class consisting of diphenyl '1. Theproduct of claim 2 in which the acid number of the resin, is between 20and 40.

8. An enamel comprising pigment, an oil modified alkyd resin having anacid number between 20 and 40, a cobalt, manganese, andlead drier. andfrom 3 to 5% of material selected from the class consisting of diphenylguanidine and triphenyl guanidine based on the resin content.

9. A coating composition adapted to dry in air,

comprising an oil-modified alkyd resin having guanidine and triphenylguanidine.

DANIEL MACE GOWING. FRANCIS SANDERS.

